Thermoluminescence of undoped and Dy-doped CaSO4: influence of the preparation methods

The thermoluminescence (TL) properties of CaSO4:Dy are used in the dosimetry of ionising radiation. Besides the characteristic emissions of Dy3+, an emission band centred at 340 nm is also observed. This UV emission range (about 340 nm) is especially interesting for 'high temperature' dosimetry which requires the use of TL peaks situated above 200-300oC, where the presence of incandescence becomes important. In this work, the influence of the preparation methods on the intensity of the 340 nm emission as well as on the characteristic emissions of Dy3+ is shown. Five products are prepared according to different synthetic routes. The influence on their TL response of some parameters such as reactional mixture, reagent purity, acidity environment, addition of charge compensating ions, etc., is discussed. TL measurements of undoped and doped CaSO4 cover the temperature range from 30 to 750oC. Moreover, cathodoluminescence spectra are in agreement with the TL spectra obtained. (author)